Extra staff are being deployed to tackle the "unacceptable" queues at Heathrow airport.
In some instances, airlines say their customers have been forced to queue for more than two-and-a-half hour hours.
Willie Walsh, chief executive of IAG, the parent company of British Airways, told Sky News: "Our customers are saying this is unacceptable, the queues are far too long and it is happening on a regular basis."
Immigration Minister Damian Green MP visited Heathrow and announced 80 extra staff are to work on the UK Border desks and plans for a new control centre to improve efficiency.
"The queues that we have been seeing recently are too long and the number of actions we're taking... are all designed to mitigate the problem, to eliminate it altogether whenever we can and to make sure that as the summer increase in passengers arrive, we can control it," he said.
Mr Green had previously appeared to play down the problem suggesting that people were overestimating the delays, something that Mr Walsh admitted left him "shocked".
Mr Walsh said: "Damian Green and the Government need to understand the scale of the problem and it is only by understanding it and accepting it that we will be confident that they can resolve it."
Top level talks between Prime Minister David Cameron and Home Secretary Theresa May have also taken place to ensure the Government delivers on the action being promised.
Detailed plans are already in place to deal with exceptional passenger numbers throughout the Olympic Games, but Heathrow operator BAA welcomed the extra staff.
A spokesperson said: "We are encouraged by the announcement of additional border resources for Heathrow and welcome the new sense of urgency being shown by the Government to tackle this problem."